1. Field of the Invention
The present invention relates to pressurized high-temperature gas coolers, and more particularly, relates to a pressurized high-temperature gas cooler which can be installed in a pressure container, such as a coal gasifier, an oil gasifier, and a biomass gasifier.
This application is based on Japanese Patent Application Nos. 2005-002058 and 2005-378724, the contents of which are incorporated herein by reference.
2. Description of Related Art
In an integrated gasification combined cycle (IGCC) system, for example as shown in FIG. 9, coal gasifier facilities which gasify fuel, such as coal, in a gasifier to produce high-temperature gas have been known.
The coal gasifier facilities include a coal supply device 100, a gasifier 200, a pressurized high-temperature gas cooler (heat exchanger) 300, a char collection device 400, and the like as primary constituent elements.
As shown in FIG. 8, the pressurized high-temperature gas cooler 300 is a device which receives a supply of high-temperature gas (produced gas) at approximately 1,100° C. containing char from the gasifier 200 and then cools the high-temperature gas to approximately 450° C., which is a suitable temperature for a gas purification device (not shown) provided downstream of the gasifier facilities, while simultaneously collecting heat energy from the high-temperature gas. In addition, this pressurized high-temperature gas cooler 300 has a flue 301 which is formed inside a pressure container 350 and which functions as a channel for high-temperature gas, and in the flue 301, heat exchangers; that is, an evaporator (EVA) 310, a secondary superheater (2SH) 320, a primary superheater (1SH) 330, and an economizer (ECO) 340, are disposed in that order from the top, so that cooling is performed by absorbing heat from high-temperature gas flowing in the flue 301 from the top to the bottom.
The structure of a pressurized fluid-bed boiler has been disclosed, for example, in Japanese Unexamined Utility Model Registration Application, Publication No. 5-71602, Japanese Patent No. 3106689, and Japanese Unexamined Patent Application, Publication No. 11-22905.
In the above structure of the related art, that is, in the structure shown in FIG. 8, a high-temperature gas outlet of the flue 301 inside the pressure container 350 provided in the pressurized high-temperature gas cooler 300 is provided at a lower side. In addition, the char collection device 400 connected to the downstream side of this pressurized high-temperature gas cooler 300 is formed so that a high-temperature gas inlet is disposed at an upper side. Accordingly, the length of a produced-gas pipe, which connects between the pressurized high-temperature gas cooler 300 and the char collection device 400, for transporting high-temperature gas cooled in the pressurized high-temperature gas cooler 300 to the char collection device 400 is disadvantageously increased in length in the vertical direction from the high-temperature gas outlet at the lower side to the high-temperature gas inlet at the upper side.
In addition, in the above structure of the related art, since the gas flow rate in the flue 301 is low, heat transfer efficiency is low, and in order to obtain sufficient heat exchange capacity, heat transfer areas necessary for the heat exchangers must be increased; hence, the necessary number of panels formed from heat transfer pipes is increased, and as a result, the cost is inevitably increased. When the heat transfer efficiency is increased, for example, by increasing the gas flow rate, the pressurized high-temperature gas cooler 300 has a long, thin shape since the cross-sectional area of the flue 301 is decreased. This is disadvantageous since the length (height) of the pressure container is excessively increased.
In addition, according to the above related technique, as shown in FIG. 10A, although the cross-section of the pressure container 350 is a circular shape, the cross-section of the flue 301 which is formed inside the pressure container 350 and in which the heat exchangers are provided is a rectangle (regular tetragon); hence, the cross-sectional ratio (cross-sectional area of heat exchanger/cross-sectional area of pressure container) is undesirably low.
According to the circumstances described above, it has been desired to develop a pressurized high-temperature gas cooler which is compact and has superior economical efficiency, which can suppress an increase in length of a pressure container while ensuring the length of a flue necessary for heat exchange, and which can ensure superior heat exchange (cooling) performance while suppressing the degradation in heat transfer efficiency.